OUTSaskatoon called the posters hateful and an act of white supremacy, and the Saskatoon Open Door Society said the posters were a threat to its staff, clients and the community on a whole.

"They're rooted in misconceptions and misreadings about immigration statistics and are also rooted in hateful, prejudiced and biased understanding of how immigration works in Canada and the Canadian society," said Ali Abukar, the executive director of the Saskatoon Open Door Society.

In the post, Clark said sentiments advocating for "dangerous old ideas of Eurocentrism and white supremacy can become a threat to the safety of families in our community and to our ability to grow as a modern global city."

"Let us continue to stand together and speak for a better city, a welcoming city and work to build understanding and belonging for everyone."

It's unclear who is behind the campaign. The Saskatoon Police Service has been notified about the posters, and said in a statement emailed to CBC Friday that its investigation was in the "very early stages."

"We cannot comment on the motives of the suspect," police said in the statement.

The posters were removed quickly from both organizations' buildings.

On Saturday, Abukar said his newcomer group has seen an outpouring of support since news of the posters became public.

The support from Mayor Clark was welcome, he said, as it shows community leaders are not going to stand for this kind of messaging in the city.

"It shows the character and strength of our community," he said, and leaves him feeling "hopeful."

"Our leaders believe that these kind of acts and these kinds of hateful sentiments have no place in our community, which makes me optimistic about what we can achieve as a community."

Several posters can be seen on the front window of OUTSaskatoon's office on Thursday. (OUTSaskatoon/Instagram)

Rachel Loewen Walker, the executive director of OUTSaskatoon, said she was shocked by the postering, as OUTSaskatoon had never been targeted by this type of act before.

On Saturday morning, she said she was pleased Mayor Clark was speaking out.

She said Clark's message sends a clear statement about the type of city Saskatoon is trying to be, and that if people see the mayor standing up against this type of messaging, others may be inspired to do the same.

"When our elected officials and our leaders stand up against hate, against white supremacy against eurocentrism, I think it does send a strong message that the rest of us too can stand up," she said.